Underreamer



Dec 33 1929. R. cRAMER 3,737,960

UNDERREAMER Filed April ll. 1928 3 Sheets-Sheet l Inventor "r 7?. 07%77767 R. cFAM ER UND-ERREAMER Filed April ll, 1925 5 Sheets-Shea?l Inventor 7F. zaffe By ,amoo M ttomqy Dec. 39 E929. R. CRAMER 1,73?,960

UNDERREAMER Filed April ll, 1928 5 Sheejs-Sheet 5 Inventor Patented Dec. 3, 192,9

PATENT OFFICE BOY GRANIER, 0F DALLAS, TEXAS UNDERREAMER Appxicatiun md Api-n 11,

The present invention relates to underreamers of a manually operable type and has for its principal object to provide a tool of this character adapted to increase the dialneter at the bottom of a post or pier hole and provided with cutting means adapted to cut a fiat bottom in the hole and to cut the sides at the bottom of the hole in an upward and inward slanting angle, substantially of a bell shaped formation, thus making an improved foundation at the bottom of the hole.

The invention further embodies the provision of a scoop or bucket adapted to provide for the removal of the dirt from the hole when removingthe tool therefrom.

A still further object of the invention is to provide a pair of pivotally mounted cutting blades at the hase of the tool adapted for spreading movement `upon the warping of the tool in a downward direction and arranged for inward movement for shifting the tool out of the hole whereby to permit the removal of the blade through the upper portion of the hole of a relatively smaller diameter.

A still further object is to provide a tool of this character of a simple and practical construction, which is strong and durable, efficient and reliable in its performance, relatively inexpensive to manufacture, and otherwise well: adapted to the purpose for whlch the same is intended. 4

@ther objects and advantages reside 1n the special construction and combination of .the various elements comprising the invention,v reference being had to the accompanying drawings, forming a part hereof, wherein:

Figure 1 is a View in side elevation with the movable cutting blade shown in a contracted position.

Figure 2 is asimilar view of the cutting or lower ends of the tool with the blades in extended positionl Figure 3 is a top plan view showing the tool blade in position as shown in Figure 2.

Figure 4 is a perspective view of one of 'the under reamer blades, and

Figure 5 is a transverse sectional View 1928. Serial No. 26S/,110. v

through the handle taken along the line 5-5 of Figure l.

Figure 6 is a view in elevation with parts broken away and shown in section, of a modified form of under reamer provided with a removal spike, and

Figure 7 is a top plan view thereof.

Referring now to the drawing in detail, the invention comprises a hand operated under reamer composed of a post 5 having a handle 6 arranged at its upper end and its lower end of a square shaped formation in cross section and slidably carried in a bucket and blade supporting frame indicated generally at 7. The frame 7 is composed of a pair of horizontally disposed frame members 8, arranged at opposite sides of the square shaped lower end of the post, the members 8 being disposed in spaced, substantially parallel relation, intermediate the ends of which and between which spaced members is arranged the upper bifurcated end 9 of a spike 10. The bifurcated section of the spike 10 form a guide for the opposite end of the squared lower end of the post 5, permitting the vertical sliding movement of the post therein.

Suspended from the upper ends of each of the horizontal members 7 is a hanger 11, at the lower end of which is formed a bucket segment 12, the segments of the pair of hangers 11 combining to form a substantially cylindrical shaped bucket with the spike 10 extending concentrically through the bottom portions thereof. The side edges of the bucket segments are spaced slightly from each other, whereby to form. an opening in the wall of the bucket extending vertically thereof, whereby to provide means for the outward swinging movement of a pair of under reamer blades 13 also suspended from' a hanger 14 by bolts 15 disposed at'the opposite ends ofthe horizontal members 7. Intermediate the upper and lower ends of the blades 13 is also pivotally attached a link 16, extending in a direction toward the post and pivotally attached to a pin 17 carried adjacent the lower end of said post. It will thus be ap arent that u on the vertical movement of t e post in t e bifurcated end of the bucket se the spike the under reamer blades 13 will be moved inwardly or outwardly with respect to the bucket segments 12.

As is clearly illustrated in Figure 1 of the drawings, the bucket segments are adapted to have the blades entirely disposed therein, so that upon the placing or removal of the tool into or out of a post hole opening, the blade will not engage or interfere with the walls thereof. 4

The construction of the underreamer blades 13 is clearly illustrated in Figure 4 of the drawings and has its outer edge curved upwardly and inwardly whereby to form a substantially bell shaped under cut at the b ottom of the post hole. The cutting edge of the underreamer blades 13, indicated at 18, extends in a direction toward which the tool is rotated, as shown by the arrows in Figure 3 of the drawin and the bottom edge of the blade is forme with a horizontal shelf 19 upon which the material may be deposited during the cutting operation.

The lower forwardly disposed edges of the bucket se ments l2 are inclined slightly downwar as shown at y20, with the inclination of the respective segments being reversed whereby to permit one edge of each of the segments to protrude downwardly beyond the edge of the adjacent segment so as to form a cutting blade and also to scoop up the loose dirt into the bucket.

In the operation of the-device, it will be apparent t at upon the encountering of the bottom of the hole with the spike 10 and pressing downwardly upon the handle 6, the

- lades 13 will be forced outwardly upon the rotation of the tool in a pro er directlon and the blades will o rate to orm an undercut at the bottom of t e hole. Upon the upward movement of the handle, the blade 13 will be moved inwardl 4 within the area of the bucket segment 12 an the tool may then be easily 4removed from the hole to permit a removal of a.v loose dirt collected in ents. y p As shown 1n Figure 5 of the drawing, the

the blade and in post 5 may be formed in sections and pro K. .1.

a sleeve 21 for fitting over the post where y to form an extension therefor, the parts being secured together by 4means of a in or other fastening .device 22.

e modified form of the invention shown `in vFigures 6 and 7 provided for the removal of the spike upon the striking of rock during the digging operation, lfor this purpose the spike being ormed into sectional portions comprising an upper section 23 and a lower section 24, the u per section being bifurcated to form. a gui e for the lower end of the post 5, as heretoforeL explained 'and having a threaded-opening in its lower end for threadedly receiving the threaded stud 25, formed on the up r end of the lower `sec spike section 24 is flattened as-s wn at 26 to receive a wrench for attaching o -removing the same. With the construction is also provided a centering'rig 27 arranged at the ends of the horizontal member 7 and of a diameter substantially equal to the diameter of the hole being dugfthe ring thus serving to maintain the tool in the center oiffthe hole.

It is obvious thatthe invention is susceptible of various changes and modifications, without departing from the spirit or scope of the invention or sacricing any'of its advantages and I accordingly claim all such forms of the device to which I am entitled. Having thus described my invention, what I claim as new is: 1. An under reamer of the class described comprising a post, a spike arranged at the lower end of the post and having a bifurcated upper end forming a guide for slidably receiving the lower'end of the post, a supporting frame attached tothe bifurcated ends of said spike, a bucket having vertically split walls a plurality ofy under reamer blades normally disposed within the bucket, hangers carried by said buckets and said blades for suspending the same from said frame, and means for connecting the lower end of the post with said bladesfor moving the blades orizontally outwardl of the walls of the bucket upon the relative vertical movement between the post and said spike.

2. An under reamer of the class described comprising a post, a spike arranged at the lower end thereof and having a lbifurcated upper end forming a guide for slidably receiving the lower end of the post, pair of horizontal frame members attache at the u per end of said spike and an under reamer b ade and a bucket segment suspended from the outer end of said horizontal member, said bucket segments combining to form the opposite sides of a receptacle with the adjacent edges spaced a art whereby to provide for the movement o the under reamer blades inwardly and outwardly with rspect thereto,

and means connecting said blades with thethe post and wit ts lower section detachably vsecured thereto, a pair of spaced substantially parallel horizontal members secured at the upper end of the upper of said spike sections,

guide for slidably receiving a guide ring carried by said members and a bucket segment, and an under reamer blade sus ended at the ends of said members.

n testimony whereof I affix my signature.

lBor CRAMER.

tion.' The sides o the upper portion of the 

